German chancellor Angela Merkel topped the list for the third straight year, ahead of Brazilian president Dilma Rousseff.

Melinda Gates - who co-chairs the Bill and Melinda Gates Foundation with her billionaire philanthropist husband - US first lady Michelle Obama, and former US secretary of state Hillary Clinton rounded out the top five.

Most powerful:

The annual list includes women who are influential in global politics, business, media, entertainment, technology and non-profits - ranking them by "money, media presence and impact," according to the business magazine.

"The rise of personal brands and entrepreneurial endeavours among this year's power women are exciting trends as we mark our 10th year of publishing the list," said Moira Forbes, president and publisher of ForbesWoman.

"From Singapore to Saudi Arabia, the United Kingdom to the United States - and beyond - the 100 influential women on our list are making an indelible and lasting impact on the world we live in."

Forbes has named Ms Merkel the most powerful woman in eight out of the 10 years the list has existed.

Other well-known faces in the top 100 include singer Beyonce (17th) and Myanmar opposition leader Aung San Suu Kyi (29th).

The 24 chief executive officers on the list lead firms with a combined $920 billion in 2012 revenues, while the eight heads of state run countries with a combined GDP of $10.2.9 trillion, the magazine said.

The 100 women on the list have a combined Twitter following of over 153 million, Forbes said.